The rage incident was sparked by a verbal dispute between Sir Meyer and boy, who is now 17, in July last year, a court heard on Thursday.
The former ambassador was getting off the train at London's Victoria station, when he nudged past the boy, who was getting on, and allegedly called him a "bastard." The teenager then ran towards Sir Meyer and knocked him down.
The former diplomat fell to the platform, suffering injuries as his glasses broke cutting his face.
The boy plead guilty to causing grievous bodily harm without, while his defence stressed that "this was a momentary lapse of judgment by the defendant, clearly a loss of temper."
"His version of events is that the complainant pushed past to get off before anyone else. He states he asked the man why did you do that, why did he push him, and that's when he said 'bastard' or 'f****** bastard'," the boy's lawyer, Brad Lawlor, told the court.
The defendant has been spared jailed on Thursday, after District Judge Wright handed him a 12-month intensive referral order and said his good character and remorse moved her to not pass a custodial sentence.
Sir Christopher Meyer served as British Ambassador to the United States from 1997 until 2003, having given evidence about his role to the Iraq Inquiry in November 2009.